By Steve Tawa

GLEN MILLS, Pa. (CBS) - As seniors at the Maris Grove complex in Glen Mills got tips on how to stay active, a group of their neighbors interrupted them. They conspired to take part in the latest phenomenon: a “Senior Flash Mob!”

Phillies Hitting Coach Gregg Gross was just hitting his stride on educating a roomful of residents on the importance of staying fit, at any age, when all of the sudden, about 25-folks burst through the doors in a flashy surprise.

All of them were wearing yellow t-shirts that read, “Fitness in a Flash.” They were lead by Evelyn Jacobs in a choreographed dance number. She says dancing “is good for your brain, too.”

“Every time you learn new steps, you’re setting up new pathways of your brain.”

Now well into their 80′s, Eleanor Caskie and Laura Ulmer were part of the flash mob crew.

“You’re never too old to try something new,’ Caskie says.

And they wrapped it up with, what else, a raffle. One lucky resident got a big screen TV.